Solderless connector for electrical conductors



June 24, 1947. Q 5T|EGL|Tz 2,422,934

SOLDERLESS CONNECTOR FOR ELECTRICAL'CONDUCTORS Original Filed Feb. 19, 1941 0 mmvrozz.

' press.

number of operations necessary in making a sol Patented June 24, 1947 soLnEnLEss oonnnc'ron'ron ELECTRICAL oormuc'rons Henry Stieglitz. St. Louis, Mo., assignor to Frank Adam Electric Company, St. Louis, Mo., a corporation of Missouri Original application February 19, 1941, Serial No. 379,607. Divided and this application February 26, 1944, Serial No. 524,114

1 This application is a division of an application filed February 19, 1941, hearing Serial Number 379,607, issued as U. S. Patent No. 2,358,745 on September 19, 1944.

This invention relates to improvements in solderless connectors.

It is an object of the present invention to provide animproved solderless connector. Various forms of solderless connectors have been used and known for some time. Some of these connectors,

consist of a casting which has a cable receiving portion that has been machined to receive a cable or wire conductor. These connectors are usually provided with a screw plug or similar cable securing means that is threaded into the cable receiving portion, and serves to hold the cable in engagement with the conductor. Although these connectors are serviceable, they are not as satisfactory as they might be because of the relatively high cost of manufacturing them. The casting and machining operations used in making these connectors are quite expensive, and materially increase the cost of manufacture. This invention avoids these expensive operations by. pro'vid ing the improved method of forming solderless connectors which consists of drawing the connectors out of a flat bar of ductile material. The result is an improved connector.

Connectors have of course, been formed by drawing previous to this invention, but have usually been drawn of thin material which. lacks strength and rigidity.

Various forms of connectors made from heavier material are known in the art but these usually require a large number of operations in their manufacture, which makes their cost prohibitive. The connector provided by this invention is formed by a method which consists in drawing a true cylindrical iormation with a round top for the cable and screw plug receiving portions, from one end of a fiat bar of ductile material.

By thus forming the connector at one end'of a bar of ductile material, a connector with a tang may be formed by a single stroke of a punch This is advantageous as it reduces the derless connector. It is, therefore, an'object of the present invention to provide an improved solderless connector with a cable and screw plug receiving portion formed integrally on one end of a. bus bar,

Various forms of solderless connectors are used today, and some of these are quite serviceable.

Many of the connectors now in use are not as serviceable as they might be, because of the num- 4 Claims. (01. 173-269) her of separate elements in them. Where a con.- nector consists of a number of elements, the electrical conductivity of the conductor is not as good as it would be if the connector was an integrated unit- Wherever two separate elements engage each other, a contact surface is formed which increases the resistance of the connector. This additional resistance makes this type of connector objectionable because the increased resistance creates more heat. The'invention obviates this objectionby providing an integrated connector. It is, therefore, an object of the present invention to provide a one-piece or unitary solderless connector.

Other objects and advantages of the invention will appear from the drawings and'the accompanying description. Inthe drawings and the accompanying description, various steps in the formation of solderless connectors'are shown and described, but it is to be understood that the drawings and the accompanying description do not limit the invention, as the invention will be defined by the appended claims.

In the drawings:

Fig, 1 is a perspective view of the solderless connector of this invention.

Fig. 2 is a cut-away perspective view of the connector shownin Fig, 1.

Fig. 3 is a side view of a screw-plug that may be .used with the connector.

Fig. 4 is'an end view of the screw plug shown in Fig. 3.

Fig. 5 is a plan view of a fiat bar from which the connector is formed.

Fig. 6 is a lon itudinal central section of the die, punch and blank at one stage of the operation.

Fig. '1 is a longitudinal cross-section through the connector with a wire in place.

Referring to the drawings in detail, a rectangular bar of ductile metal is denoted by the numeral 20. This rectangular bar must be'of a, ductile metal that is a good conductor of electricity. Such a metal is commonly copper but any suitable metal may 'be used. The rectangular bar is operated on tomake the form of a solderless connector shown in the drawings. For the purposes of illustration, the drawings show the result of a number of operations performed in sequence on the rectangular bar to The connector may be formed in a progressive die which may be used in a. punch press. In making the type of connector shownin Fig. 1, a series of operations is performed which will now be described.

Before being placed in the drawing die, one end of the bar 20 may be cut in the form of a curve, as indicated by the numeral 22 in Fig. 5, and an opening 24 may be punched in the other end of the bar. :I'he hole 24 is used to secure the removable connector to a bus bar and may receive a bolt or similar fastening means. The bar 20 is then placed in a specially designed drawing die and drawn into the shape shown in Fig. 1. The drawing of the bar 20 into a true cylindrical formation is done by a drawing punch which draws the bar into a die to form the cylinder and continues to punch out the hole 26 in the same operation. This operation is essentially a drawing operation since the punch moves into the die and draws the metal along with it, thereby forming the cylindrical shaped cable and screw plug receiving portion. In the drawing operation, the bar 20 is drawn into the die until it is folded back onto itself. The vertical lines in the side of the cable and screw plug receiving portion of the connectors, are the abutting edges of the rectangular bar 20.

Fig. 6 above shows the relation of parts just before the opening 26 is punched. The blank 20 has been drawn from the depression l in the top of base 18, into the cylindrical cavity ll of the die I 9, by upward movement of cylindrical punch l1, forming the cylindrical portion l6. Continued movement of the punch will cut out the disc 26 as the end of the punch passes-into opening 25 of the die, to form opening 2'6 in the upper end 0f cylinder Hi.

When the metal has been drawn into the shape indicated in Fig. 1, it is in contact with the die and can not be drawn farther. The punch, however, continues to move and is forced through the metal. The die into which the bar 20 is forced, has an opening to receive the punch and permit this to pass through thermetal and form opening 26. It should be noted that the inside of the cylindrical formation is formed by the same punch that cuts the hole 26. This makes the diameter of the opening substantially the same diameter as the inside of the cylindrical formation. Punches are then used on the cable and screw plug receiving portion of the connector to form an opening 28 therein. The hole 26 in the cable and screw plug receiving portion is then threaded to receive the screw plug 32. The screw plug will hold the smallest size wire which the connector is designed for in a fixed and lasting connection. It can be seen that as the diameter of the opening is substantially the same as the internal diameter of the cylindrical formation, that the threaded portion extends, as is shown in Fig. 2, a substantial distance down the internal walls of the cylindrical formation. This screw plug 32 may have a rounded end with concentric grooves 34 on its face, that engages the cable or wire inserted in the connector, and secures it. It can be seen that the connector is formed of one piece of material and that the electrical conductivity thereof is considerably better than that of a connector formed of several parts. It can also be seen that this connector may be made of drawn copper rather than of cast copper or other conducting material. It should be noted that sufficient threads are provided to prevent the screw plug 32 from unscrewing through vibration or other causes and releasing the conductor. With this connector, either stranded or solid conductor may be used without necessitating special forming of the wire.

Whereas a preferred embodiment of the inven- 'tion has been shown and described, it will become apparent to those skilled in the art that various changes in detail may be made without altering the scope of the invention as defined by the appended claims.

What I claim is:

1. A one-piece solderless connector of copper bar stock, said connector having an inverted cupshaped cylindrical portion open at the bottom, a flat bar portion integral with and extending from the bottom of said cylindrical portion, an opening through the top of said cup-shaped cylindrical portion, the internal diameter of the opening being substantially the same as the internal diameter of the cylindrical portion, a pair of opposed sharp-edged openings through the cylindrical portion of the connector and aligned with the flat bar portion of the connector, threads through the opening and down into the cylindrical portion, and a securing means engaging said threads adapted to depress a conductor inserted through the opposed openings below thebottom edge of said openings.

2. A one-piece solderless connector of copper bar stock having an inverted cylindrical cupshaped portion, said portion having an external circumference, a bar portion integral with the cup-shaped cylindrical portion and forming an extension thereof, the external circumference of the cylindrical portion being more than double the width of the extension, a pair of opposed sharp-edged openings through the sides of the cylindrical portion aligned with the extension, an opening in the top of the cup-shaped cylindrical portion, the internal diameter ,of said opening being substantially equal to the internal diameter of the cylindrical portion, threads extending through the opening and into the inside of' the cylindrical portion, a scouring means engaging said threads, the cylindrical portion being open at the bottom and the securing means being adapted to depress a conductor inserted through the opposed openings below the bottom of said openings.

3. A one-piece solderless connector of copper bar stock adapted to be secured to electrical devices, said connector having a cylindrical inverted cup-shaped portion open at the bottom, an extension of said cup-shaped portion, said extension'being a bar of conducting material integral with the cup-shaped portion, an opening in the bar extension, said opening being adapted to allow the connector to be secured to electrical devices, a pair of opposed sharp-edged openings in the side walls of the cylindrical portion aligned with the extension of the connector, an openingin the top of the cup-shaped cylindrical portion, said opening having an internal diameter substantially equal to the diameter of the inside of the cupeshaped cylindrical portion, threads extending through said opening and on the inside of the cup-shaped cylindrical portion, a screw plug engaging said threads and adapted to engage a conductor when inserted through the opposed openings, a rounded portion around the bottom edge of the cup-shaped cylindrical portion opposite the extension thereof.

4. A solderless connector of copper bar stock adapted to be secured to electrical devices, having an inverted cup-shaped cylindrical portion open at the bottom, a flat bar portion integral with and extending from the cup-shaped cylindrical shaped portion at the bottom thereof, an opening through said bar portion adapted to allow the securement of the solderless connector to i 2,422,934 r v 5 i 6 an electrical device, Opposed sharp-edged openings through the side walls of the cup-shaped REFERENCES CITED cylindrical portion adapted to receive a conduc- The w nz r r n s are of record in the tor, an opening in the top of the cup-shaped cyfile of this P t lindrical portion, said opening having an inter- 5 UNITED nal diameter substantially equal to the internal STATES PATENTS diameter of the cup-shaped cylindrical portion, Number Name Date threads extending through the opening and into 2,222,156 ROWE NOV. 1940 the inside of the cup-shaped cylindrical portion, 2,043,512 Hoover June 1936 and a screw plug engaging the cup-shaped cylin- 10 2,083,923 ROWE June 1937 drical portion, said screw plug being adapted to 2,201,674 R w e a1 M y 21 ,1940 clamp a wire when inserted in the opposed opening.

'HENR-Y M. s'rIEGLITz. 

